BackFire
Blood. It's nature's lube
Bonnie and Clyde - A quintessential violent/robbery movie. Also simply an outstanding film, as good as it is important.
Taxi Driver - Same as above, a very important, influential and unique film for its time, a shocking use of violence at the end of well, again, for its time.
Irreversible - Unforgettable film with some of the most effective use of violence ever, like it or hate it, it will affect you.
Kids - A movie (it is) with an important theme and message that is very relevant to the current generation, a movie that should be seen at least once, you'll either love it or hate it probably.
Salo - Same type of thing as Irreversible. A film that you won't ever forget, and that will affect you in some way or another. Considered to be the most disturbing and disgusting film ever made, I don't disagree. A terrifying portrait of the seemingly infinite depths that a human being can reach.
Scarface - It's violent, and it's kind a cult movie, it's neat.
Dog Day Afternoon - A great bank robbery movie, deserves more credit than it gets, a great movie.